1. Line a 12-cup muffin tin with paper or silicone baking liners.
2. Add the graham crackers and coconut sugar to a food processor and process until it forms a fine crumb. Add the melted coconut oil and process until well combined. Use a tablespoon to divide the mixture evenly into the muffin cups, pressing the crust firmly into the bottom and up the sides of each cup. Place in the freezer while you prepare the filling.
3. Blend the coconut milk, chia seeds, sugar, salt, and lemon juice in a blender on high speed for 2 minutes. Note: A blender rather than the food processor is necessary to grind the chia seeds to the correct consistency, important for the texture of the filling. Add the melted coconut oil and blend on a lower speed until incorporated, stopping to scrape down the sides as needed.
4. Divide the filling evenly into the graham cracker crust muffin cups, using a small spatula to smooth out the filling. Refrigerate for at least four hours.
5. To make the topping, mix the strawberry preserves with one teaspoon of water and stir to combine. Gently spread ½ teaspoon over the top of each tartlet. Add the sliced strawberries in a decorative fashion and serve cold. Keep leftovers refrigerated.
Note: To make this recipe into a pie instead of tartlets, lightly grease a 9-inch pie plate or springform pan. Press the crust into the pie plate and follow the directions for the filling and topping.